Grounded socket casing



P 1934- H. HUBBELL, JR 1,974,049

GROUNDED SOCKET CASING Filed Feb, 2, 1932' Patented Sept. 18, 1934 7 Claims. (onus-35s);

Thisinvention relates to new and useful improvements-in sockets for electric bulbs and-has particular relation-to a grounded sooket'casing for use in a portable lamp structure such as the trouble lights used in garages, factories and the like. An object of-the invention is to providea lamp socket, particularly foruse in portable lamp structures and including means whereby themetalcasing or cap of the socketis grounded by a conductor preferably leading from the-interior of the socket and also preferablyincluded in the usual rubber covered cable'containing the two power leads or conductors. V 7

Satisfactory embodiments of-the invention are shown in the accompanying drawing and described in detail in the following specification. However, it is to be understood that the drawing and description-areforthe purpose of disclosure and that the invention is not confined to the details shown but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims. g In-the drawing: 7 Fig. 1 is aside elevationalview of a portable or trouble light in accordance with the invention, parts of the groundedsocket casing being broken away; r I

Fig. 2 is .a detail view showing the upper portion of the casing, the view being taken at right angles to'Fig. 1 and parts of the upper portion of the casingbeing broken away; i

Fig. .3 isa perspective view ofa'metal washer employed in thesocketoi Figs l and 2; p

Fig. lisaview somewhat similarto Fig.2 but showing the device-equippedwith a modified form or structure of washerpand- Fig.. 5 is a perspective view of Referring in detail to .the'drawingand at first particularly to Figs. 1; 2 and 3, the improved socket the washer used generally designated 6 is shown as applied to a portable or troublelight including a handle '7 and a'lamp or-bulb 8 threaded into the socket 6 in the usual mannerj The socket 6 comprises a metal casing including ametal shell9 lined with paper or other insulating material 10 and a cap 11 also of metal and'providedwith a paper or other insulating liningv l2. The cap ll'ashere'shown includes a flange or skirt portion 13 surrounding the upper endportion 'o f the. metal shell and a ring 14 serves to connect'thecapand shell.

Within the casing is any or theiusual blockpf insulating material 15 carrying any or the usual connections 16 each. equipped with. a binding screw or .post 17 and formingelectrical 'connec tions with the usual central and'screw-sh'ell lamp contacts, not shown. At its end opposite its skirt portionlB the cap 11 is provided with an end wall 18 having'a'n opening therethrough and throughwhich opening extends a reduced portion 19 ofya ferrule 20 comprising part of the handle 7.. The ferrule-is internally screw threaded as at 21 and is adaptedto have the reduced externally threaded screw porti0nw'22 of' 'a'handpiece- 23 threaded therein. Through the handle 7 thereis carried a cable 24 including a pair of conductors25and 26 each connected with one of the binding'posts. or screwsl'll Of course, wires'or conductors 25 and 26. arethe power leads to the socket 6 and are adapted to supply current for energizing; the lamp orbulb 8. I As will be clear from an inspection of Figs. 1 and 2, a shoulderx27-results toward the inner end of the ferrule 20-when the reduced portion 19 of the ferrule is formed: When the'ferrule is. applied to the cap '11 this shoulder 27 of the ferrule engages thelou'ter surface of the end wall 18 of-the cap andagainst 'theinner surface of said-wall thereis disposed a metal washer28 including anannularsbody portion 29 having an ofi-set portion tapped as at 31ifor thereception of avbindingscrew'32p The washer 28 is held in firm engagement with the inner surface of the end wall 18 of the cap whereby a good electrical oonnectionis provided and this washer may be formed of copper or other material. To secure the washer in place and also to secure the ferrule to the cap the inner end of the reduced portion '19 of the ferrule is rolled or riveted over as at 33 against the underside of the Washer.

' 'The parts are therefore securely united with the washer-infirmengagement with the cap and disposed'withincthe cap whereby to all outward appearances the socket 6-is of the usual construction. A third or grounding conductor34 is preferably included in the cable' 24 with the conductors 25 and 26 and this grounding conductor 34 is secured about the'binding screw or post. 32

or clamped beneath the head of the binding screw or post and the under surface of the" offset pgrtion 30 of the washer 28. I It will be evident thatwithout the grounding COlIdllCtOl'Bfl: thesocketjfi is insulated and if one ofthe leads or conductors 25 and 26 become loose and touch the shell'or cap the operator would probablybe injured if his handcame in contact with the shell or caps However. withthe presentarrangement the shell and cap portions ofthe casing are in contact as usual and the Washer,

til

28 is in contact with the cap portion of the casing and is connected with the grounding conductor 34. Therefore, should one of the power leads or conductors work loose and come in contact with any portion of the metal casing the casing Will be thoroughly grounded through the conductor 34 and a workman would not be injured should he touch the shell.

Figs. 4 and 5 disclose a slightly modified construction of washer, the other parts being constructed as described in connection with Figs. 1 and 2. In this modified construction the washer generally designated 35 is at one side provided with a depending arm 36 carrying an outwardly inclined ear 37 tapped as at 38 for the reception of a binding screw 39. 'The bind.-.

ing screw 39 is, of course, adapted to have the grounding conductor 34 connected therewith and the washer 35 is held in engagement with the inner surface of the end wall 18 of the cap 11 by riveting or rolling over the inner end portion of the ferrule as at 33.

Since the device of Figs. 4 and 5 functions as already described in connection with Figs. 1 through 3 further description is believed unnecessary although attention is directed to the fact that in either form of the device the washers are tightly clamped against the metal casing and particularly the "cap portion thereof and the grounding wire or conductor is connected to a binding post on the washer.

If desired, and as a further safety feature, a disc of insulating material 40 may beprovided in the cap 11 and between the binding post 32 and the binding post 17.. This disc 40 is preferably formed of a relatively stiff insulating material-"as compressed fibre.- Further, the disc is provided with a pair of spaced perforations for V the passage of the conductors or leads 25 and 26 40' and in operation this plate is to prevent the conductors or'leads 25 and 26 from moving around freely in the socket should they become free of their binding posts 16. The disc will also prevent the-exposed ends of the conductors 25 and 26 from coming into engagement with the'binding post 32 of Figs. 1 and 2 or 39 of Fig. 4. I

Having thus set forth the nature of my invention, what I claim is: v

l. A lamp socketincluding a metal casing having an opening through an end wall thereof, a metal washer within said casing, a handle including a portion clamping said washer against the inner surface of the end wall of the casing, a pairof contacts in said casing, said contacts adapted to be engaged by the contacts of a bulb, a pair of conductors extending through said opening and connected with said pair of contacts, and a grounding conductor connected with said metal washer and extending out of the casing.

2. A lamp socket includinga metal casing having an opening through an end wall thereof, a metal washer within said casing, means clamping said washer against the inner surface of the end wallofthe casing, a. pair of contacts in said casing, said contacts adapted to be engaged by the contacts of a bulb, a pair of .conductors extending through said opening and connected with said pair of contacts, said washer having a portion thereof offset inwardly of the casing, and a grounding wire connected with said portionof the washer and extendingv out of the casing. 3. A lamp socket including a metal casing hav: ing an opening through an end wall thereof, a metal washer within said casing, means clamping said washer against the end wall of the casing, a

pair of contacts in said casing, said contacts adapted to be engaged by the contacts of a-bulb, a pair of conductors extending through said opening and connected with said pair of contacts, said washer having a portion thereof offset inwardly of the casing, a grounding wire connected with said portion of the washer and extending out of the casing, a perforated fibre disc extending transversely of the casing between the washer and said pair of contacts,-and said pair of conductors extending through the perforations in said disc.

4. A lamp socket including a metal casing having an opening through an end wall thereof, a

ferrule extending through said opening, a metal washer against the inner surface of said end wall of the casing and about the opening therein, said ferrule having a shoulder against the outer surface of the end wall of the casing, said ferrule having an inner portion engaging the washer whereby the washer and end wall of the casing are clamped between said inner portion and shoulder of the ferrule, a hand piece threaded into said ferrule, a pair of contacts within the-casing, said contacts adapted to be engaged by the contacts of a bulb, a pair of conductors extending through said hand piece and ferrule and connected with said contacts, said washer havinga portion offset inwardly of the casing, a binding post on said offset portion of the washer, and agrounding wire connected with said'binding post and extending through said ferrule and hand piece'and included in a cable with said pair of conductors.

5. A lamp socket including a metal casing having an opening through an end wall thereof, a ferrule extending through said opening, a metal washer against the inner surface of said end wall of the casing and about the opening therein, said ferrule having a shoulder against the outer surface of the end wall of the casing, said ferrule having an inner portion engaging the washer whereby the washer and end wall of the casing are clamped between said inner portion and shoulder of the ferrule, a hand piece threaded into said ferrule, a pair of contacts within the casing, said contacts adapted to be engaged by the contacts of a bulb, a pair of conductors extending through said hand piece and ferrule and connected with said contacts, said washer having an ear at one side thereof and extending inwardly of the casing, a binding post on said ear, and a grounding wire connected with said binding post and extending through said ferrule and hand piece and included in a cable with said pair of conductors;

6. A lamp socket including a metal casing having an opening througha wall thereof, a ferrule extending through said opening, a metal washer against the inner surface of said wall of the easing and about the opening therein, said ferrule having a shoulder against the outer surface of said wall of the casing, said ferrule having an inner portion engaging the washer whereby the washer and said wall of the casing are clamped between said inner portion and shoulder of the ferrule, a pair of contacts within the casing, said contacts adapted to be, engaged by the contacts of a bulb, a pair of-conductors extending through said ferruleand connected with said contacts, said washer having a portion extending out of the plane of the washer, a binding post on said portion of the washer, and a grounding wire connected with said binding post and extending through said ferrule. 7

7. A lamp socket including a metal casing having an opening througha wall thereof,a handle including a portion extending through said openfoo its

its

a metal washer against the inner surface of said wall of the casing an said handle having a s (1 about the opening houlder against the said Wall of the casing, said handle on engaging the washer 6. said wall of the casing outer surface of having an inner porti whereby the washer an contacts, and a grounding wire connected with said washer and extending out of said casing.

HARVEY HUBBELL, J R. 

